New York, May 12 (IANS): Covid-19 vaccines are safe in pregnancy and cause no injury to placenta, say researchers, dispelling vaccine hesitancy among pregnant women.

The placenta is the first organ that forms during pregnancy. It performs duties for most of the fetus' organs while they're still forming, such as providing oxygen while the lungs develop and nutrition while the gut is forming.

Additionally, the placenta manages hormones and the immune system, and tells the mother's body to welcome and nurture the fetus rather than reject it as a foreign intruder.

"The Internet has amplified a concern that the vaccine might trigger an immunological response that causes the mother to reject the fetus," said Jeffery Goldstein, Assistant Professor of pathology at Northwestern University's Feinberg School of Medicine.

But the study, published in the journal Obstetrics & Gynecology, shows that it "doesn't happen." The findings showed that the Covid vaccine does not damage the placenta -- abnormal blood flow between mother and baby in utero.

The team collected placentas from 84 vaccinated patients and 116 unvaccinated patients who delivered at Prentice Women's Hospital in Chicago and pathologically examined the placentas whole and microscopically following birth. Most patients received vaccines -- either Moderna or Pfizer -- during their third trimester.

The scientists also looked for abnormal blood flow between the mother and foetus and problems with foetal blood flow -- both of which have been reported in pregnant patients who have tested positive for Covid.

The rate of these injuries was the same in the vaccinated patients as for control patients, Goldstein said.

The scientists also examined the placentas for chronic histiocytic intervillositis -- a complication that can happen if the placenta is infected, in this case, by SARS-CoV-2. Although this study did not find any cases in vaccinated patients, it's a very rare condition that requires a larger sample size (1,000 patients) to differentiate between vaccinated and unvaccinated patients, the researchers said.